present invention relates generally to fluorescent lamps, and more particularly to ultraviolet fluorescent lamps providing different ultraviolet radiation characteristics adjacent one end.
As is well known, tanning is the result of the body's reaction to exposure to ultraviolet radiation. Tanning can provide protection against the sun's rays, and it may also serve a cosmetic function in that many people desire to exhibit the healthiness represented by a desirable tanned appearance.
As a result, tanning salons are becoming very popular, and tanning lamps are also purchased for home and club use. Many devices have been developed to make tanning with the use of artificial illumination sources more enjoyable and efficient. Generally, tanning salons use a booth, chamber, or bed, in or on which a person is placed for exposure to ultraviolet tanning radiation from a number of lamps. Generally, the tanning bed or chamber has a multiplicity of fluorescent lamps that extend longitudinally along the length of the individual and disposed in a parallel array of a width which will uniformly expose the full width of the body. Typically, these lamps are approximately six feet long, or the height of an individual.
Most ultraviolet tanning fluorescent lamps have been uniformly coated with a fluorescent material to provide a uniform radiation intensity over the length, and as many as "several dozen" lamps may be used in a single bed or chamber.
It has been recognized that, in most individuals, the facial area may require different ultraviolet radiation characteristics than the radiation area provided to the body in order to obtain the desired uniform tanning effect. In part, this may be due to higher levels of melanin in the skin in the facial area due to its greater exposure to the sun.
Merely increasing the intensity of the ultraviolet radiation may provide increased tanning effect, but an ideal approach to providing increased tanning effect in an area of the body would involve altering not only increasing intensity but also increasing the ratio of UVB to UVA rays so that greater melanin production is stimulated.
As is also well known, shorter wave ultraviolet light of 260-320 nanometers (UVB) stimulates the production of the pigment melanin by the melanocytes in the skin. Once the melanin has been produced, the longer wavelength ultraviolet light of 320-400 nanometers (UVA) darkens or oxidizes the melanin granules which are produced and thereby generates the tanning effect. Thus, in most effective tanning lamps there is present in the radiation both UVB and UVA rays with the UVB rays stimulating the production of melanin which migrates upwardly towards the horny layer or corneum of the skin where the UVA then oxidizes the melanin to produce the tanning effect. The UVB radiation is also desirable from the standpoint of producing a thickening of the skin to provide protection from excessive radiation. To remedy this, some tanning beds or chambers also use metal halide lamps in the area of the head to provide increased radiation to the facial area. Still others interpose relatively short lamps between the longer lamps to provide desired additional intensity or characteristics for the radiation in the facial area. In this way, the overall duration of time spent in the tanning bed or chamber is held constant while the ultraviolet radiation is increased in intensity or varied in its spectral characteristics in the facial area of the individual to provide the desired uniform tanning over the entire body. Although these composite tanning beds or chambers may provide the desired uniform tanning effect, they are more complicated to fabricate and maintain, and they are relatively expensive.
A lamp which will provide different radiation characteristics Schlitt U.S. Pat. No. 4,967,090 granted Oct. 30, 1990 attempts to provide different spectral characteristics in a single lamp by applying different phosphor coatings to discrete circumferential portions of the lamp. Thus, his lamp may be rotated to change the UVB/UVA characteristics rather than by providing different lamps with uniform characteristics.
It is an object of the present invention to provide a novel ultraviolet lamp that has a portion adjacent one end thereof providing ultraviolet rays of different characteristics than those over the remainder of the lamp.
It is also an object to provide such a lamp which may be fabricated relatively easily and economically, and which will exhibit a relatively long life.
Another object is to provide a tanning bed or chamber which is of relatively simple construction using only these novel lamps so that it can be easily and inexpensively manufactured and maintained, while providing the desired tanning effect by generating different radiation characteristics over the facial area of the individual.